One-pot Synthesis And Enhanced Catalytic Properties Of Low-/Non-Platinum Nanostructures

Metal nanomaterials with hollow structure are of great interest due to their new structure,unique performances (e.g., high specific surface area, high surface activity, strong surfacepermeability, low density etc.), and novel physical and chemical properties such as excellentcatalytic activity. At present, many methods have been reported for the preparation of hollownoble metal nanoparticles. However, these strategies usually company with relativelycomplicated procedures and low efficiency, and are generally used to fabricate a single metalnanocrystal. Therefore, for realizing and broadening practical applications of hollow metalnanocrystals, it is of key importance to design a simple and general synthetic route. In thisthesis, we demonstrated, for the first time, a general one-pot approach for the synthesis ofhollow noble metal nanoboxes via galvanic replacement reactions of Ag nanocubes served astemplates. Their components, structures, sizes, shapes, and catalytic activities werecharacterized by transmission electron microscopy (TEM), high-resolution TEM (HRTEM),X-ray diffraction (XRD), X-ray energy-dispersed spectroscopy (EDS), X-ray photoelectronspectroscopy (XPS), UV-visible absorption spectroscopy (UV-vis), and cyclicvoltammograms (CV). The major results of the thesis are as follow:1. Uniform Ag nanocubes were synthesized by the reduction of silver nitrate (AgNO3)with ethylene glycol (EG) in the presence of poly (vinyl pyrrolidone)(PVP) and sodiumsulfide (Na2S). Using the Ag nanocubes as templates, the mesoporous Pt/AgCl nanocubeswith the average edge length of about46nm were obtained through galvanic replacementreaction without centrifugation and separation. Very interestingly, without using anysupporting materials, the mesoporous Pt/AgCl nanocubes show outstanding electrocatalyticactivity. The electrochemically active surface area (ECSA) and catalytic activity of themesoporous Pt/AgCl nanocubes produced thus are about3times and10times higher thanthose of their nanoparticles prepared by traditional method, respectively.2. A facile, efficient, economical, and one-pot route to synthesis hollow Pd/Ag alloynanoboxes is demonstrated. Moreover, the Pd/Ag alloy nanoboxes have excellentmonodispersed in aqueous solution, and show outstanding electrocatalytic activity withoutintroducing any loading materials. The results show that the Pd/Ag alloy nanoboxes producedthus exhibited higher electrocatalytic activity (more than10-fold) than the Pd nanocubesprepared by traditional method.